I came very close to having this problem on a front wheel of my 1025R. A routine front wheel replacement resulted in a galled female thread. It's a less common metric thread, so I had no tap in the kit. I was able to chase out the damaged thread by cutting an extra bolt I had.
What is pictured as your "thread chasing tool" is indeed a tap. It's okay to use for this, if you are very careful. As said. by hand only! Two thirds a turn in, one third a turn out (so it cuts back the building chips of the four flute tap), all the way in until it spins in freely. Lots of lubrication. The tap must be square to the hole. If not, it'll try to cut a new thread off axis.
If you're now past that repair, installing a helicoil is your next best option. You'll have to buy a heilcoil kit for that thread size, which will include a drill, a special tap, and some helicoils. In my opinion, for this application, installing a helicoil is machining work requiring precision and care. You will be cutting a new threaded hole, which must be on axis and square to the surface. I'm not saying that it can't be done on the tractor, but you get one chance to get it right. figure out a means to very precisely square the hole to the surface of the flange. The hole can be drilled by power (at a very slow speed), but still, the tapping must be at hand speed, in and out as described. Review helicoil installation instructions and videos. A very common process.
Happily, a helicoil repair to a female thread is stronger than the original, and much less likely to ever bind again. Really well made equipment, where removing/reinstalling bolts is intended, often come with helicoils already (some expensive cameras tripod mount threaded hole).
If you're considering a weld type repair, that is certainly specialized work, find a machine shop who say that they have the capability.
